>> >> > > If you define a new protocol version as one that means devices with > older protocol generations of firmware/software may not interoperate > reliably with devices with new protocol generations of > firmware/software, then IPv4 as we know it today is probably at least > "IPv7" - address classes was a generational change requiring > software/firmware updates (compare addressing in rfc760 verses rfc791), > as was classful+subnets and then CIDR. > > Regards, > Mark.
I think it's defined, instead, in terms of incompatible changes to the content of the packet header. Owen
